Surgical apparatus or instruments, wherein tissue is first grasped or clamped between opposing jaw structures and then joined by means of surgical fasteners are well known in the art. In some such instruments a knife is provided to cut the tissue which has been joined by the fasteners. The fasteners are typically in the form of surgical staples, although, other surgical fasteners may also be utilized, such as, for example, clips or two part polymeric surgical fasteners.
Instruments for applying surgical fasteners typically include two elongated beam members which are respectively used to capture or clamp tissue therebetween. Typically, one of the beam members carries a disposable cartridge assembly which houses a plurality of staples arranged in at least two lateral rows, while the other beam member includes an anvil which defines a surface for forming the staple legs as the staples are driven from the cartridge assembly. Where two part fasteners are used, this beam member typically carries the mating part, e.g. the receiver, to the fasteners driven from the cartridge assembly. Generally, the staple formation process is affected by the interaction between one or more longitudinally moving camming members and a series of individual staple pushers. As the camming members travel longitudinally through the cartridge carrying beam member, the individual pusher members are biased laterally, thus acting upon the staples to sequentially eject the staples from the cartridge. A knife may travel with the camming members or the individual pusher members between the staple rows to cut the tissue between the rows of formed staples. Examples of such instruments are disclosed in U.S. Pat. No. 3,079,606 and U.S. Pat. No. 3,490,675, each of which is incorporated herein in its entirety by reference.
A later surgical apparatus or instrument, disclosed in U.S. Pat. No. 3,499,591, incorporated herein in its entirety by reference, applies a double row of staples on each side of the incision. This is accomplished by providing a cartridge assembly in which at least one camming member moves through an elongate guide path between two sets of staggered staple carrying grooves. Staple pushers are located within the grooves and are positioned in such a manner so as to be contacted by the longitudinally moving camming member to effect ejection of the staples.
A need exists for improved surgical fastener applying apparatus, and for improved mechanisms and methods for producing improved surgical fastener applying apparatus.